Javascript newValue始终等于单元测试中AngularJS属性中的oldValue
我有一个控制器,它只是监视一个“name”属性,并在任何更改时打印它的新值和旧值Javascript newValue始终等于单元测试中AngularJS属性中的oldValue,javascript,unit-testing,angularjs,jasmine,Javascript,Unit Testing,Angularjs,Jasmine,我有一个控制器,它只是监视一个“name”属性,并在任何更改时打印它的新值和旧值 function Ctrl($scope) { $scope.$watch('name', function(newValue, oldValue) { console.log('newValue: ' + newValue + ', oldValue: '+ oldValue); if (newValue !== oldValue) { //...
function Ctrl($scope) {
$scope.$watch('name', function(newValue, oldValue) {
console.log('newValue: ' + newValue + ', oldValue: '+ oldValue);
if (newValue !== oldValue) {
//...
}
}
});
然后我想用Jasmine进行单元测试:
var rootScope, scope, ctrl;
beforeEach(inject(function ($rootScope, $controller) {
rootScope = $rootScope;
scope = $rootScope.$new();
ctrl = $controller('Ctrl', { $scope: scope });
}));
it('should have different old and new values if I set a new name', function() {
rootScope.name = 'some new name';
rootScope.$apply();
//expect the behaviors happen for newValue !== oldValue
});
然后我希望控制台记录一条消息,指示newValue不等于oldValue,但是我总是得到newValue===oldValue。为什么旧价值会丢失?我认为,这就是行为。当我们第一次调用控制器时,旧值等于新值,因此不会发生任何事情。通常在这种情况下,我们可以写:
if(oldValue === newValue){return;}
我们还可以编写$watch
如下:
$scope.$watch('name', function () {
// ....
});
并且仅当名称
发生更改时才会调用:
演示1
我不是最团结的大师,无论如何,试试这个流程:
控制器
angular.module('plunker').controller('MyCtrl', function($scope) {
$scope.watchFunctionCounter= 0;
$scope.$watch(function () {
return $scope.name;
},
function (newValue, oldValue) {
console.log('newValue: ' + newValue + ', oldValue: '+ oldValue);
if (newValue !== oldValue) {
$scope.watchFunctionCounter++;
}
}, true);
});
Unitest
describe('Directive: maybeLink', function() {
var scope, ctrl;
beforeEach(function() {
module('plunker');
inject(function($rootScope, $controller) {
scope = $rootScope.$new();
ctrl = $controller('MyCtrl', {$scope: scope});
});
});
afterEach(function() {
controller = null;
});
it('should have different old and new values if I set a new name', function() {
scope.name = 'some new name';
scope.$digest();
expect(scope.watchFunctionCounter).toBe(0);
// on this strage the name is undefined, therefore we stay out of "if" statemant
scope.name = 'diff name';
scope.$digest();
expect(scope.watchFunctionCounter).toBe(1);
});
});
演示2我所做的是在控制器创建之后立即在beforeach子句中运行摘要:
beforeEach(inject(function ($rootScope, $controller) {
rootScope = $rootScope;
scope = $rootScope.$new();
ctrl = $controller('Ctrl', { $scope: scope });
scope.$digest();
}));
这样,在运行每个测试之前都会完成摘要,并且手表工作正常。是的,正如您的代码所演示的,让我困惑的是,为什么第一次通过
scope.name='some new name'
设置新值时,您会得到oldValue
等于newValue
并且计数器没有递增?这就是我的困惑:-(